Abstract: The present disclosure describes a device to force open the door of a safety deposit box having a lock. The device comprises a key having an end terminated by a portion extending in a direction perpendicular to the longitudinal axis of the key, the end being adapted to be inserted into the keyhole of the lock, the portion extending sufficiently in the direction so that the portion can rest against the interior surface of the door beyond the cylinder of the lock after that the key has been inserted into the keyhole and laterally displaced with respect to the cylinder. The device also comprises a puller for pulling the key, the puller having a fastening mechanism for securing the key to the puller, and legs adapted to rest against a solid surface adjacent to the door which can be forced open by pulling the key while the portion rests onto the interior surface of the door, by means of the puller having its legs resting against the solid surface.